DRX Cycle Length Adjustment Control

1. A method implemented by a wireless transmit/receive unit (WTRU), the method comprising: the WTRU receiving information indicating a first DRX cycle length and a second DRX cycle length; the WTRU receiving a DRX trigger; the WTRU determining whether to perform DRX using the first DRX cycle length or the second DRX cycle length based on the received DRX trigger, wherein the WTRU performs DRX using the first DRX cycle length if the received DRX trigger is a first type of DRX trigger and the WTRU performs DRX using the second DRX cycle length if the received DRX trigger is a second type of DRX trigger, the second DRX cycle length being a multiple of the first DRX cycle length; and the WTRU performing DRX using the DRX cycle length determined based on the received DRX trigger.

2. The method as in claim 1 , wherein the received DRX trigger is the first type of DRX trigger, and the method further comprises: the WTRU starting a DRX cycle length transition timer; the WTRU determining that the DRX cycle length transition timer has expired; and the WTRU transitioning to the second DRX cycle length upon determining that the DRX cycle length transition timer has expired.

3. The method as in claim 2 , wherein the second DRX cycle length corresponds to a normal DRX cycle length.

4. The method as in claim 2 , wherein the DRX cycle length transition timer is started upon beginning DRX operation using the first DRX cycle length.

5. The method as in claim 2 , wherein a length of the DRX cycle length transition timer corresponds to a resume period.

6. The method as in claim 1 , wherein the received DRX trigger comprises a downlink command.

7. The method as in claim 1 , wherein the DRX trigger is implemented at a medium access control (MAC) level.

8. A wireless transmit/receive unit (WTRU) comprising a processor and memory configured to: receive information indicating a first DRX cycle length and a second DRX cycle length; receive a DRX trigger; determine whether to perform DRX using the first DRX cycle length or the second DRX cycle length based on the received DRX trigger, wherein the WTRU is configured to perform DRX using the first DRX cycle length if the received DRX trigger is a first type of DRX trigger and the WTRU is configured to perform DRX using the second DRX cycle length if the received DRX trigger is a second type of DRX trigger, the second DRX cycle length being a multiple of the first DRX cycle length; and perform DRX using the DRX cycle length determined based on the received DRX trigger.

9. The WTRU as in claim 8 , wherein the received DRX trigger is the first type of DRX trigger, and the processor and memory are further configured to: start a DRX cycle length transition timer; determine that the DRX cycle length transition timer has expired; and transition to the second DRX cycle length upon determining that the DRX cycle length transition timer has expired.

10. The WTRU as in claim 9 , wherein the second DRX cycle length corresponds to a normal DRX cycle length.

11. The WTRU as in claim 9 , wherein the processor and memory are configured to start the DRX cycle length transition timer upon beginning DRX operation using the first DRX cycle length.

12. The WTRU as in claim 9 , wherein a length of the DRX cycle length transition timer corresponds to a resume period.

13. The WTRU as in claim 8 , wherein the received DRX trigger comprises a downlink command.

14. The WTRU as in claim 8 , wherein the DRX trigger is implemented at a medium access control (MAC) level.

15. A base station comprising a processor and memory configured to: send a message to a wireless transmit/receive unit (WTRU) that indicates a first DRX cycle length and a second DRX cycle length; and send a DRX trigger to the WTRU, wherein the DRX trigger is one of a first type of DRX trigger or a second type of DRX trigger, wherein the first type of DRX trigger indicates to the WTRU that the WTRU is to perform DRX using the first DRX cycle length and the second type of DRX trigger indicates to the WTRU that the WTRU is to perform DRX using the second DRX cycle length, the second DRX cycle length being a multiple of the first DRX cycle length.

16. The base station as in claim 15 , wherein the DRX trigger is the first type of DRX trigger, and the processor and memory are further configured to: determine that the WTRU has transitioned from the first DRX cycle length to the second DRX cycle length based on a DRX cycle length transition timer at the WTRU having expired.

17. The method as in claim 1 , wherein the information indicating the first DRX cycle length and the second DRX cycle length is received via higher layer signaling.

18. The method as in claim 1 , wherein the information indicating the first DRX cycle length and the second DRX cycle length is received in a radio resource control (RRC) message.

19. The WTRU as in claim 8 , wherein the information indicating the first DRX cycle length and the second DRX cycle length is received via higher layer signaling.

20. The WTRU as in claim 8 , wherein the information indicating the first DRX cycle length and the second DRX cycle length is received in a radio resource control (RRC) message.